Halloween is one week away, and to celebrate, we're turning our gaze to the dark side of life hacking. This is Lifehacker's Evil Week.

The whole "evil" thing is a bit tongue-in-cheek, but one common theme unites most of what we're covering this week: Knowledge is power, and whether you use that power for good or evil is in your hands. On first blush, your reaction to discussing a topic like password cracking, for example, may be negative, but a better understanding of pasword security can motivate you to bolster your security or simply provide you with the tools to break back into your own system should you find yourself locked out. As we said during last year's Evil Week, there's a time and place for "bad behavior." That time is now on Lifehacker. Welcome to Evil Week.